Projector for light signals



Fb. 25, 1930. s. M. DAY,- I r 1,748,913-

PROJECT OR FOR LIGHT SIGNALS Original Filed on. 17, 1921 2 Sheets-Sheet '1 25, I930. S. M. DAY I PROJECTOR FOR LIGHT SIGNALS I original Filed Oct/17. 1921 2 Sheets-Sheet 2 Fig.4.

. I PIC-3 3A 3 I 155% FIGS;

a 38 FIG.6. 5 \\\\\\\\\\\\w C l 5; 1 2e Patented Feb. 25, 1930 SALISBURY M. DAY, or nocnnsrna, new Yon-n, assieivon roennnaar. SIGNAL co uranv, or noci-rns'rnn, new YORK RA LWAY r aoJncron 'roi z. LIGHT SIGNALS Original application filedcctober 1'7, 1921-, Serial no. 508,194 Divided and this application filed December 29, 1924.. Serial 1 \To. 758,665. r

s This invention relates to light signals for railway signaling purposes, and morepar 7 should be ticularly to light projectors for such signals.

Color light signals in their typical form comprise anumber of light projecting units with different colored lenses, as red, green, yellow or the ,like and the diiferent signal indications are given-by lighting the electric lamps of these units'one at a time as desired so as to project a beam of colored light. In such a-signal, while-the energy consumption as low as possible, especially where primary'b atteries are to be used, the signal should be ableto give a positive and arrestive indication at a comparatively long range, such'as 3,000 or @000 feet, and also through a wide angle of spread so as to be visible even though the observer, on account of a curve in the track or other conditions, should not be directly in line with the slgnal. Also, a satisfactory day light. signalshould be capableot giving such an indication under most. unfavorable light cond tlons, that 1s,'w1tha sky background and with strong sunlight shining directly in the face of the signal or observer. These practical working conditions i demand an eiiicient light projecting system;

and whilea concentrated filam-entelectric lamp aiiordsa satisfactory lightsource for this purpose, in order to obtain the desirable range of indication and angle of spread with the least amount of energy consumption, it is desirable to utilize as much of the light from the lamp as possible; It will be evident that the ordinary. n v and projecting onlya small part-of the total lightemitted from the filament of the lamp,

that'is, only a portion of the totaljspherical candle power of the amp. The use of reuse some ofthelight emitted backward and sidewise ofthe le'nsfrom' the lamp,'is' objectionable in practice because of theten-dency to produce false signal md1cat1ons, commonlytermed phantom signals; I Such phantom signals are caused by light from an outsidesource, such as" sunlight or a locomotive headlight, which passes into the signal and is reflected or difiused'backout, making the signal appear as if it were lighted;

lens is capable ofreceiving I flectors orcurved mirrors, in an .attempt'to- Another important characteristic of a color light signal adapted for practical working conditions in railway. signaling is the provision of a reserve source of light. The. elec- 'tric lamps of'the signal of course burn out from time to time,'and rather than have the burnlng out of a lamp extingulsh all lndicatlon and make adark signal, it Is desirable to have a reserve orauxiliary lightv source the filament of the new lamp in each instance should be in the proper position with relation to the focal point of the lens orotheroptical device of the signal. Electric lamps manufactured commercially on a large scale, however, do not have their filaments, or more strictly speaking, the luminous center of their filaments, in any definite fixed relation with respect to the bulb or its base; and when a new commercial lamplis inserted'in' a signal, it is usually necessary to adjustthelamp slightly in some suitable way sons to bring its filament at the desiredpointr Suchad j ustment is awkward and expensive, 'a'ndjre-v quires two experienced workmen, oneto make the adjustment, and the other to standatp distance anddetermine from the appearance accordance with the present invention to provide an arrangement oflenses, conveniently termed a doublet combination, together with a lamp having a double or duplex convoluted filament symmetrically located :with respect to these lenses, so as to utilize a large signals above pointed out, it is proposed in proportion of the total light emitted'frOm the filament these doubleifilaments being 7 preferably constructed so that one will burn longer than the other; and in order to facilitate the replacement of burnt out lamps, the invention contemplates a scheme of manufacture or construction of signals and lamps, so that any lamp may be inserted in any signal, and regardless of inaccuracies in the location of its filament incident of manufacture on a commercial scale, the filament will in every instance be at the proper point with respect to the lens combination of that particular signal.

In the practical application of light signals to the varying conditions of railway signaling, it is found that various aspects and different applications and the like ofsupport for the signal are required. For example, at one time one may want a signal capable of giving two different indications, commonly termed a two-position signal, at another time 'a threepositionsignal. In order to get these require ments in the simplest manner, and more particularly obviate necessity of manufacturing and keeping in stock a large number of parts to make up the various combinations required, it is proposed in accordance with the present invention to design the light signal casing and other parts so that they are symmetrical and interchangeable and any of the component parts may be combined together directly and without affecting previous adjustments to make up a large variety of combinations or assemblages.

Other features and advantages of the invention will appear as the description progresses.

In describing the invention in detail, reference will. be made to the following drawings, in which:

Fig. 1 is an enlarged front View of a twounit light signal, portions thereof being broken away for clearness;

Fig. 2 is a side view of the light signal shown in Fig. 1 illustrated in the same manner;

F ig. 3 is a sectional view taken on the line 8 -3 of Fig. 4 as viewed in the direction of the arrows; V

Fig. 3 is a fragmentary sectional view on line 33 of Fig. 3, viewed in the direction of the arrow; r

Fig. 4 is an enlarged view, illustrating the inside bezel ring and the lamp socketand lamp adj ustably mounted thereon;

Fig. 5 is a fragmentary sectional view taken on the line 5'5, Fig. 1, and shows the sighting arrangement; and r Fig. Gillustrates the glass of the sighting device most clearly shown in Fig. 5.

This application is a division of the prior application .of Salisbury M. Day, for colored light signals, filed October 17, 1921, Ser. No. 508,194.

According to the preferred embodiment of the invention, the signal is made up in its various combinations of identical light projecting units, with casings and various adapters such that these units may be assembled together' to provide signals giving any desired number and arrangement of indications. One of these units Willbe first described in detail, before considering the different Ways in which the parts of these units may be interchang'e'ch Referring more particularly to Figs. 1 and 2, each signal unit comprises in general a boxlike casing C, which is preferably made of cast iron so as to have the necessary strength and rigidity. This casing O is formed with a large circular opening in its front wall, and is provided with an open-back closed by a movable door 1. This door 1 may be connected to the casing O in any suitable manner, but in the construction shown the door is formed with integral lugs at one side which are hinged on cotter pins or the like supported by pairsof lugs integral with one side wall of the casing C, so that the door may be swung back and expose the entire inside of the casing. The door 1 is also preferably provided with a suitable spring hasp fastener 2 for pressing the door inward with a gasket 3 in a groove around the door seated tightly against the edges of the casing O. A ventilating opening 4 (see Fig. 2) is provided in the door 1, and this opening is protected by a suitable bulging cap or weather shield fastened by screws to the door over the opening 4: and also by a screen suitablylsecured inside of the door.

The top and bottom walls of the casing C are constructed identically, and have a. raised ridge 5 around the edge which is accurately machined in manufacture, a central beveled or cup shaped opening 6, and four holes 7. By reason of this construction, two casings C may be fastenedtogether by bolts 8, as shown in Figs. 1 and 2, with their machined ridges 5 contacting and lining up these casings.

A light projecting unit, comprising a lamp and its socket, the inner and outer lenses of the doublet combination, and a suitable hood,

is detachably fastened to the front wall of the casing C. This light projecting unit com prises a tubular tapered casting 9, conveniently called a lens barrel, which is formed with an outer flange fastened by four bolts to the front wall of thecasing G, as best shown in Figs. 1 and'2. The outer lens 11 of the'doublet combination bears around its edges directly against the bottom of a groove or rabbet formed in the larger end of the lens barrel 9. This outer lens 11 is held in ,place by a retaining member.

12 which is fastened to the lens barrel 9 by four screw bolts 13, a gasket 14 of felt or the like, being preferably interposed between this retaining member 12 and' the edges of the lens 11. This retaining member 12 is formed with four notches in its edge, as shown in Fig. 1, to receive the heads of the bolts .10 and prevent them from'turning.

theselbolts being preferably provided with jam nuts;

7 upper part'of the retaining member12, and

integral therewith, is a forwardly projecting flange 12 to which is fastened by screw'bolts a curved sheet metal hood or shield 15'. The

inner lens 16 of the doublet Combination also seats at its edge in a" groove or rabbet'in the lens barrel 9, and this inner lens is held in place by a retaining member or ringi17, which is fastened by threescrews 18-to the lens barrel .9, a similar gasket being interposed between the lens barrel-9 and this lens.v It will be noted that the lenses 111and 16 bear directly against finishedsurfaces on the'lens barrel 9 and the ring 17 fastened thereto,and since these surfaces'are accu rately formed in manufacture, and the lenses, beingmolded, are identicah -ijt will be evident that-the lenses always havethe proper fixed spacing and relation'in each signal unit. 1

The inner'and outer; lenses 11 and 16 are of the well known Fresnel or stepped type, the steps or corrugations being formed on the inner surface of the outer lens'll', and

the outer surface of the inner lens 16. lhe outer lens is clear or colorless, whilethe inner lens is made of a glass, having the desired" shade .of red, green, yellow, or the like, for the appropriate signal indications.

The purpose ofthis combination orarrange 'ment'of lenses is to utilize as much of the total light rays or flux emitted by the fila-y ment as it is practicable to obtain without the use of reflectors and their objectionable tendency to produce phantom indications, and without employing movable color screens. orother moving parts. In this arrangement oflen'ses, which may be conveniently termed adoublet combination the incandescent constituting the. source of light is "10-.

cated with its filament asclose-to the inner lens-16 as permitted-by the sizeof the lamp construction 1 shown,

1 bulb needed to take care of radiation. and also the-practical clearances'required to allow insertion and removal'of the lamp. It will be evident that the closer. the filament is to the lens, the greater portionof the total power of the filament will spherical candle H be received by the lens; and m the specific cone of light, rays a plane angl of 158 de light flux glven off by thejfilamentfalls upon the inner lens.

' The inner lens 16 ismade with its inner sur- 7 face-concave and?"with prismatic zones of spherical curvature on its outer surface.

Theseizones are designed in accordance with established optical'principles so as to converge the lightrays'emanating from the fila- 'men ii'ponthe outer larger-lens 11'. The

inner lens has an apparent focus at a po nt Extending" partway 7 around the" it can be seen that the. falling upon the inner lens embraces a solid angle corresponding approximately to grees, so that about 40 per cent of the total a behind the-lamp, preferably at the apex of the angle embraced by the outer edges of the two lenses. .The: outer lens 11 has its outer convex surface smooth, and is formed with zones ion -its inner surface nal may be seen by the. engineer of a train as it approaches the signal, comes around a curve, or is traveling on anfup or down grade'toward the signal. Of course, asthe spread of the-beam is increased, its cross section is. increased, .and consequently for the same candle power, the intensity of the beam is decreased; and these antagonistic factors are proportioned and selected to conform with'practlcal .workmg conditions, so as to provide a-lightqprojecting" system visible through the desired angle of spread and at the desired range or distance,

with a minimum energy consumption. ,A

furtherpoint regarding the spread ofthe signal is that the curvatures of thezones, on the lower portion'of the outer lens 11 are preferably modified, so asto direct some-light downward from the main beam directly in front ofJthe signal, in'order' that a reasonably strong signalindication may be visible by the engineer of a locomotive pulling directly. up to and standing undernthe signal, this being; particularlyv important Where the signal is mounted on I a high pole iorion a signal The lamp 19 employed'in each signal unit is preferably formediwitha double or duplex concentrated filament. In the particular construction illustrated, two parallel vcon'voluted filaments 20 are secured to the usual pair'oflead-in-wires 'andzthese filaments are intendedto have a difierent length of life,

being preferably made'of a difierent length or'cross section so far 'as'ipracticable inordinary manufacture, so as to have vdiflerent resistances and. burn'at different temperatures; These filaments 20. are. located close together and. are, positioned symmetrically about the I point at which-'theilight source'shouldbe located-.. Both ofjthe filamentsare inthe lighting, circuit, and-since one will almost always burn outb'efore the other,-the remain ing filament constitutes ai'z'eservelight source which is strong enough to give a recognizable indication,but weak enough; to show that a.

new lamp is needed. .Thus, th'ejdouble' fila ment lamp, in addition to providing an effident and effective concentratedsource oflight,

meets that important requirement of railway point where the light source should be located,

base in the bayonet slots.

, cal slots in saidextension's, so that the bracket rather than at a considerable distance out of focus, so to speak, as it necessarily must be when afiorded by an extra lamp.

Since accurate location of the light source is important in signals of this character, the manner in which the lamp-is mounted or supported in the signal should be such as to hold the lamp firmly and positively in the proper position, even though carelessly put in place, or subjected to considerable jar and vibration, while at the same time the lamp should be readily movable to permit replacement; To satisfy these requirements, it is proposed to employ the usual bayonet type lamp base and socket. The lamp base is accurately formed in manufacture, or an auxiliary base or support is attached thereto after manufacture, or in some other suitable way constructed or adapted so that the filament has a definite relation with respect to the surface of the base and pins determining the position of the lamp when inserted in a socket. The pinsin the base of the lamp are also located with respect to the plane of the double filament'so'that this filament faces the lens; The particular design of apparatus for rebasing or constructing such standardized lamps with a uniform and 'accurate location of their filaments with respect to their bases,.and* the specific construction of the released lamps, forms no part of the present invention, and is described and claimed in applications filed by R. C. Leaks, Sept. 24:, 1921, Ser. "No. 502 955, and by E. VJ. Moore, Sept. 30, 1921, Ser. No. 504,456 respectively.

The socket or receptacle to receive the lamp is of the usual type and comprises a socket or she'll proper 21, which is formed with'bayonet slots, and is fastened to a block 22 of porcelain or similar insulating material. In this block 22 is supportedthe usual spring pressed plunger or contact pin (not shown), which engages the center contactof the lamp and also seats the pins on the lamp This porcelain block 22 is also provided with the usual terminal posts for wires. and is fastened by two screw bolts 23 (see Figs; 3 and 4) to an angle bracket 24,'these b'olts passing through enlarged holes in the bracket so as to permit the block to be adjusted. to various positions inthe laueofthebracket; The angle bracket 24 is secured'by bolts 25 ateach-end to downwardly projecting extensions on the retainingring 17, the bolts passing through vertimay be raised and lowered, or tilted.

The pbrcelain block 22 is accurately adjusted. with the aid of a suitable fixture during manufacture or assembly, so that the axis of the socket shell 21 and the bottoms of bayonet slots have a definite relation with respect to the bezel ring 17, and consequently with respect to the lenses. Such adjustment takes care of any slight variations in size and shape that may occur in commercial manu facture of the porcelain blocks 22, socket shells 21, angle brackets 24, and associated parts. In other words, the lamp socket of each signal is individually adjusted during manufacture in such a way that any lamp, rebased or adapted to fit that type or style of signal, may be put in any socket, and the filament of that lamp will come at the proper great difficulty is encounteredin providing a simple and effectiveway of communicating the necessary information from the-observer to the'sign'al. Tofa'cilitate such adjustment, a simple and effective sighting'device for the signal is provided by this invention. This sighting device in general comprises spaced apertures in the casing which are accurately located during manufacture with respect to the lenses, so that the line'of sight afforded v by'this device conforms with the direction in which the beam of light will be projected from the signal. tion illustrated (see Figs. 5 and 6), a glass disc 26 is fitted in a small circular openingin thefront' wall of the signal casing C near one upper corner, this disc being. held in place by a suitable bezel ring fastened to the casing. At the rear end of the casing C, back of the disc 26, a small peep. hole 27 is In the particular construebored in a small web integralwith thecasing.

The glass disc 26 is preferably provided with a ring 26" (see Fig. 6) which is sand blasted thereon, painted or otherwise made opaqueor nearly so. lVhile one pair of these sighting apertures is-sufiicient for any one signal, regardless of the number of unitsmaking. up that signal, for simplicity and convenience in manufacture, it is preferred to provide each unit with these sighting apertures.

Upon looking throughthe small peep hole 27,.the clear glass of thedisc 26outside of thelring 26 affords a relativelyilarge field for spotting objects and determininga coarse adjustment, while the small hole inside of the ring 26 forms a small'field for accurate sighting. Ifdesired, the large field may be proportioned to correspond approximately 1 with the area-of the beam of light from the signal, so that. an observer can determine roughly,'at least, how to point the signal so as to be visible from the desired points along thetrack. This sighting device greatly facilitates the adjustment: of the signals for ment;1and this sighting device, while-effective and suiiiciently. accurate for all prac-= tical purposes, ischeap and simpleandmay .be made with a permanent part of each signal 'unit, thereby making 1t unnecessary. for

- point 'with respect to the lenses.

workmen to carry around special toolsand: implements for settlng up and ad ustmg signals. In this way, once thelamp: socket has been-accurately disposed with respect to the lenses,-any rebased or standardized lamp may be inserted in thissocket, and the filament of thatlamp will come at the proper 1 This is an important feature 'ofthe invention, since lamps when. manufactured in quantities by T commercial methods, do not have-their. filaar-e put in signals to replace those burntout,

v 7 for that new lamp isordinarily necessary to. obtain an effective light-projection; 'and'as' this adjustment is difiicult to perform in -thisfield, ,it is evidently of great practical. ad-,. vantage to be able to replace burnt-out lamps. when necessary by merely putting in another lamp standardized to fit that signal without ments accurately located withrespectito-their bases, so that when such cominerclal lamps or otherwise unfit for. service, an adjustment adj ustmenttilted Another feature of thesignal disclosed report for the signal means of which it may be'mount'ed upon the top of the usualtubular pole, or on a suitable bracket, and turned or Figs. 1 and 2, this'support or. adapter 30 comprises a tubular portion tapered at" the poles or other round supports varying in .d1- ameter, the ends of these poles seating tightly.

- against this tapered surface. A pluralityof port 30 and are provided withthe usual lock When these screws 31 are; loosened, the whole support 30 may be turned around the pole, eo'

adjusting screws 31, four being shown, are

threaded in the tubularportionof the supnuts.

and-by adj usting these'screws, the support may be tilted at any desired angle 7 in: any vertical plane. rFWhen thesescrews are tightened, the support 30' is rigidly fastenedto'the'pola. The upper endofthe support 30 isformed witheai'shelf or-table 'inthe middle ofwhiehin any desired direction. Referring to- 'is raised rounded boss32, having a'hole therein through which wires may pass. This table of the support 30 is pro-vided with four holes to'receive bolts 8 'for securing the cas in g C thereto. This boss 32 is shaped" to'fit' in the-socket formed'by the beveled opening 63in thecasing C, and provides in effect a ball and socket connection; and by tighteningea'nd looseningthe bolts 8e, the casing C may be tilted with respect to the support 30.

Thus, thereis provided a coarse and a fine adjustment for'setting the signal in any desired angle to throw the beam along'the track for short or long range, up or down grade,

receptacle and the hood15, the, same parts may be used to make up. a signal in which the doors swing either rightor lefthanded.

through the tubular pole, through a hole in the boss 32 of the support 30, and beveled hole'fi into the lower signal casing, and thence to the upper signal casings through the hole 6in their adjacent walls,'bushings .36 of Wood or similar insulating material being preferably inserted in these --holes as The lamps 19 maybe energized when.re-' quired by wires (not shown) brought in' shown in Figs. 1 and-2; Suitable terminal blocks may be'provided for facilitating the attachment and connection of'wires. The top of the uppermost signal casing 6 is finished with a simple cover plate 38, as shown.

It should be noted that the light projectin unit comprising the lens barrel 9, inner andouter lenses, and lamp receptacle are detachable and interchangeable,1 so that light projecting units giving difi'erent coloredin- 3 dications may be shifted-about during instalj lations, or after the signals are in service, as sides'in theprov1s1on of an ad ustable sup- J may be desired. Changes in the color of the indication of the various units'may also be screws 18 and detachment, of the bezel ring .17.. While the light projecting units are detachable and interchangeable, each is rigidly. upper end and onthe-1ns1de so asto receive attached to the casing and will alwayscome i eral signals. Referring to Fig. 2, it will an outwardly projecting flange, which is :clamped againstithe outer face of thecasing G by the bolts 10. These engaging surfaces accurately in the proper position'in the ,sev-

and the holes for the bolts arexaccurately finished during manufacture with the aid of suitable tools and fixtures, so that any giv light'projecting-unit may be attachedto any signal casing.

The outer lens 11 can be easily and quickly removed from theoutside ofv the casing by merely taking out thebolts 13 anddetaching the hood and outer retainingi'member 112;.

This construction facilitates the replacement of a broken outer lens and also enables the stepped surfaces of the two lenses to be cleaned when necessary. In case of a defectivfe lamp or broken porcelain block 22, rather than replace the block and socket alone, a procedure which might necessitate a re-adjustment of the parts for the best results, a new unit comprising the bezel ring 17, angle bracket 24, block 22 and the socket 21 is substituted for the defective unit, and since :these units are identical, it is assured that the new socket shell will be accurately lo.- cated with respect to the lenses, and upon the insertion of a standardized lamp will position the filament of that lamp at the right point. In short, it will be observed that the signal constructed in accordance with this invention allows any of the various parts likely to wear out, or become damaged in service, to be easily and readily replaced in the field without the need for special adjustment and effectiveness of the signal.

The particular construction of light projeetor shown and described is susceptible of considerable modification and adaptation in practice, and I desire to have it understood that my invention is not limited to the specific embodiments herein disclosed, except as indicated by the claims.

What I claim is 1. Ina light signal, in combination, a casing, a lens, means mounting the lens in the casing, a substantially ring shaped lens retaining member bearing directly against the lens and havin a .downwardl )ro'ectinv.

b 2': portion, a bracket, means ad ustably securing the bracket to said downwardly projecting piortion and a lamp socket secured to said brac et r 2. In a light signal, in combination, a casing, a lens, means mounting the lens in the casing, a substantially ring shaped lens re-' taining member bearing directly against the lens and having .two downwardly projecting legs, a bracket adjustably secured to said member by means of bolts passing.

through slots in said legs, and a lamp socket secured to said bracket.

.3, In a light slgnal, 1n combination, a cas- 7 mg, a lens, means mounting the lens in the casing, .a substantially ring shaped lens retaining member bearing directly against the lens and having two downwardly projecting legs, a bracket adjustably secured to said member by means of bolts passing through vertical slots in said legs, said bracket having a shelf portion extendlng behind said member at an acute angle thereto, anda lamp socket secured to said shelf portion of said bracket.

4. In a light signal, in combination, a signal casing, a lens,means removably supporting the lens in one wall of the casing, a re .taining member for holding the lens "in the I weenie planes substantially at right angles to eachother, while retaining the relationship of the axis of said lens and the plane defined by the bayonet slots and the axis of said receptacle substantiallyconstant.

5. In a light signal, in combination, a boxlike casing having an opening in its front wall, a light projecting unit comprising, a tapered lens barrel, inner and outer stepped lenses seated in circular recesses in the ends of said barrel, a retaining ring for the inner lens, a lamp'socket, means supporting the socket on said ring, and a retaining member forthe outer lens, said lens barrel having a flange at its outer end and means detachably fastening the flange to the front wall ofthe casing. V

v6. A light projecting unit for color light signals comprising, a tapered lens barrel, inner and outer stepped lenses of difierent diameters supported in said barrel, a retaining member of inverted U-shape for holding the smallerinner lens in position in the lens barrel, a. lamp receptacle, and adjustable means supporting said receptacle from said retaining member and permitting movement of the receptacle with respect to said retaining member vertically and horizontally with respect to the axis of said lenses.

7. A light signal unit for railway signallin purposes comprising, a casing having a ront wall, the front wall of said casing having an opening therein, a lens barrel in said opening, means securing said barrel to said casing, inner and outer stepped lenses, means securing said lenses in the lens barrel and including an inverted U-shaped retaining member for holding said inner lens in said barrel, said retaining member having downwardly projecting legs, an incandescent lamp socket, and means adjustably securing said socket to said legs.

.8. A light signal comprising a signal casing, an opening in one wall of said casing, a lens support secured in said opening, a lens with a simple focal point positioned in said support, a retaining ring secured to -said lens support for retaining said lens in said support, and a lamp socket secured to said retaining ring for positioning a light source at said focal point, said lens support and attached 7 bracket.

ing through vertical slots in said legs, said bracket having a shelf portion extending v behind said member, a lamp socket, and means adjustably mounting said socket on said shelf portion.

10. In a light signal, in combination, a casing, a lens, means mounting the lens in In testimony whereof I afix my signature.

SALISBURY M. DAY. 

